Black oil, low power, 6.5liter 1995 GMC problem

4520 Views 7 Replies 5 Participants Last post by cnctech, Jan 29, 2007

cnctech

Discussion Starter · Jan 29, 2007 (Edited)

Hello,
This is my first post. What a great site!
I very recently bought my first diesel, a 1995 GMC 3500HD 6.5liter turbo flat bed. I know little about diesels, so I have a few questions.
I changed the oil after having it about a week. The old oil was as black,
as coal, and stained my hands like it had carbon in it.
I checked the oil after probably 1000 miles and it was three quarts low, with no leak being noticed.
Other conditions are:
The power output is low.
The vacuum pump locked up after I had driven it about a week.
The check engine light comes on often for about five seconds.
The fuel mileage is terrible.
Starts fine.
Mileage is 170k miles.
Oil pressure is 40 psi warm running, 20 psi warm idle.
Did I buy a dog?
Thanks for any help you experienced fellows may have.
Charles

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Scrufdog

· #3 · Jan 29, 2007

cnctech;1556363; said:
Hello,
This is my first post. What a great site!
I very recently bought my first diesel, a 1995 GMC 3500HD 6.5liter turbo flat bed. I know little about diesels, so I have a few questions.
I changed the oil after having it about a week. The old oil was as black,
as coal, and stained my hands like it had carbon in it.
I checked the oil after probably 1000 miles and it was three quarts low, with no leak being noticed.
Other conditions are:
The power output is low.
The vacuum pump locked up after I had driven it about a week.
The check engine light comes on often for about five seconds.
The fuel mileage is terrible.
Starts fine.
Mileage is 170k miles.
Oil pressure is 40 psi warm running, 20 psi warm idle.
Did I buy a dog?
Thanks for any help you experienced fellows may have.
Charles

are you sure you put enough oil in it? About 7-8 quarts. Diesel oil gets jet black after about 2 seconds of being in a diesel, thats normal. It means its doing its job by trapping soot in it. Oil pressure is good.

Power output, vacuum pump and Check Engine light are probably all the same problem.

The wastegate on the turbo is controlled by vacuum. If no vacuum is present you wont get much power. The computer sees a problem and sets off the light. Get a scanner and check the codes and let us know.

Follow the Troubleshooting Checklist in the FAQ and post results. Keep your signature updated so we know what truck and engine you have. Get the 8th digit of the VIN, should be either an F or an S

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Scrufdog

· #6 · Jan 29, 2007

cnctech;1556687; said:
Talking about quick assistance!
Thanks,
Will consult faqs
Sorry about breaking the conventions here.
Cnctech

not breaking anything, just pointing you in the right direction

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